The present invention relates to a process control system, and more particularly, to a method for dynamically varying the monitoring process when the grade of the product being produced by the process control system is changed without shutting down the process control system.
In current systems, the quality control scheme is disrupted every time a grade/brand change is made on a production line of a process being controlled by the process control system. The process is stopped, the system reinitialized and/or adjusted for the change in the grade/brand, and the system started again. This results in less precise statistical control during the start-up portion of each production run, when the process is likely to be least stable and require the most adjustment.
The method of the present invention makes the change in grade/brand without shutting down the system thereby providing the same level of statistical precision in monitoring the first sample in the production run of the newly selected grade/brand as is available for a well-established running continuous process.